iMac stayed on just fine during 2 power failures, yet froze up completely . . .

[Anonymous user]

iMac stayed on just fine during 2 power failures, yet froze up completely . . . and beyond that, it required a hard power-button shut-down

which left me with corrupt directories ( as is often the case ) on 2 or 3 externals.

I'm sure the iMac and the externals are plugged into the correct side of the UPS, but it would take an hour to dismantle the surrounding area and trace all cords for 100% confirmation.
The fact that they stayed on during the failure bears this out.

My point is, what use is the Mac remaining on if it completely freezes ( even the clock in the upper right toolbar froze ) and a hard shut-down has the same file and directory ruining effect as an unprotected power off ??

[BillP]

David,

What is the model of the UPS and do you have the USB cable attached? If the USB cable is attached have you configured Power Saver option or have you install a shutdown app?

[Anonymous user]

Thanks for the reply, and please return in 24 hours or so.
I have to disassemble the area surrounding the UPS to access and freely move it, and right now it happens to be my "Monday morning".
( wake-up, get it together, and get back to work ).

There's also the fact that the light that indicates the UPS doesn't fully "approve" of the power-outlet has been red all along as well.
How deeply key is that ?

[Anonymous user · Accepted solution]

On 8/18/2016 2:52 PM, David said:

There's also the fact that the light that indicates the UPS doesn't fully "approve" of the power-outlet has been red all along as well.
How deeply key is that ?

The red "site wiring fault" light indicates a couple of possibilities: either the hot/neutral wires are swapped or the safety ground is open.

Either problem should be corrected by a qualified electrician. Without a safety ground, the surge suppression functionality of your UPS will be greatly reduced.